There is an electronic power tool currently existed in the market, which includes a motor, a gearbox, a pushrod for extending and retracting a cutter, a cutter library, a cutter holder; the motor is connected with an input member of the gearbox; an output member of the gearbox is connected with the pushrod; after an end of the pushrod entered the cutter holder, the pushrod drives the cutter holder to rotate; alternatively, the output member of the gearbox is connected with the cutter holder, and the output member drives the cutter holder to rotate. No matter which mechanism is chosen, in general, a first gear is set on the output member while a second gear is set on the pushrod or the cutter holder, and the fist gear engages with the second gear to reach the connection. Consequently, the output member is not coaxial with the cutter holder. Moreover, the space is needed to set up the pushrod. As a result, the electric power tool would be large in circumferential size, complicated in structure, and not compact enough. In order to push the cutter into the cutter holder, the pushrod is capable of moving axially and there are two available positions. Position One: the pushrod is retracted and therefore brings the cutter that located in the cutter holder to be stored in the cutter library; at this time, the cutter library is rotatable, and users can turn the cutter library to select a cutter; after selected, the pushrod extends forward to push the cutter into the cutter holder, which is the Position Two. The structure would be quite complicated as the structure should be designed to fit the axial movement of the pushrod. At the same time, when the cutter holder is rotating, the pushrod should also be rotating accordingly, which consumes considerable energy. The other end of the pushrod is generally connected with a sliding base, and the pushrod is rotatable relative to the sliding base. Consequently, the other end of the pushrod and the sliding base would be worn out because of the relative rotation, which would shorten the service life of the electronic power tool.